Tag Archives: blindness

DNA test for congenital cataracts leads to faster, more accurate diagnoses of rare diseases linked to childhood blindness

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Ophthalmology_Pediatrics

Researchers in the United Kingdom have demonstrated that advanced DNA testing for congenital cataracts can quickly and accurately diagnose a number of rare diseases marked by childhood blindness, according to a study published online in Ophthalmology, the journal of the American Academy of Ophthalmology. Using a single test, doctors were able to tailor care specifically to a child’s condition based on their mutations reducing the time and money spent on diagnosis and enabling earlier treatment and genetic counseling.

Each year, between 20,000 and 40,000 children worldwide are born with congenital cataracts, a disease that clouds the lens of the eye and often requires surgery and treatment to prevent blindness.[1] The disease can arise following a maternal infection or be inherited as an isolated abnormality. Congenital cataracts can also appear as a symptom of more than 100 rare diseases, making mutations in the 115 genes associated with congenital cataracts useful as diagnostic markers for the illnesses.

Diagnosing these rare diseases previously proved a lengthy, costly and inconclusive process involving numerous clinical assessments and taking a detailed family history. DNA testing, one gene at a time, would have taken years to complete. Employing new DNA sequencing technology, called targeted next-generation sequencing, researchers at the University of Manchester sped up diagnosis to a matter of weeks by testing for mutations in all 115 known congenital cataracts genes at one time.

In 75 percent of the 36 cases tested, the DNA test determined the exact genetic cause of congenital cataracts. In one case, the DNA test helped diagnose a patient with Warburg Micro syndrome, an extremely rare disease that is marked by an abnormally small head and the development of severe epilepsy, among other medical issues. Having a clear diagnosis allowed for genetic counseling and appropriate care to be delivered quicker than previously possible without the test.

“There are many diseases that involve congenital cataracts but finding the exact reason was always difficult,” said Graeme Black, DPhil., professor of genetics and ophthalmology at the University of Manchester and strategic director of the Manchester Centre for Genomic Medicine. “Even with a family history, diagnosing these rare diseases was always a bit of a shot in the dark.”

In the course of their work, done in collaboration with Manchester Royal Eye Hospital, researchers also found previously undescribed mutations linked to cataract formation. “There is hope that our work may one day provide more insight into the development and treatment of age-related cataracts, a leading cause of blindness worldwide,” said Rachel Gillespie, MSc, lead author of the study who designed and developed the test.

The test was made available to U.K. patients through the country’s National Health Service in December 2013. Infants and children who have congenital cataracts can be tested as well as prospective parents with a history of the condition who wish to evaluate the risk to their child. Results generally take about two months. While only available in the U.K., the congenital cataract DNA test can be requested by registered medical facilities through international referral.

As with all genetic testing, the American Academy of Ophthalmology encourages clinicians and patients to consider the benefits as well as the risks. Ophthalmologists who order genetic tests either should provide genetic counseling to their patients themselves, if qualified to do so, or should ensure that counseling is provided by a trained individual, such as a board-certified medical geneticist or genetic counselor. For more information, please see the Academy’s recommendations on genetic testing for inherited eye diseases.

 

http://www.medicalnewstoday.com/releases/281442.php

 

 

 

Wearable computer gloves ‘help teach braille’

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Ophthalmology

More than 39 million people around the world are blind. For many of these individuals, braille – a reading and writing system that utilizes a series of raised dots that represent letters, numbers and punctuation – is a valuable tool. Now, researchers from the Georgia Institute of Technology have developed a wearable computer glove that can teach braille, even when the user’s attention is on another activity.

The research team – including Thad Starner, a professor at Georgia Tech and a technical/lead manager on Google’s Project Glass – first created a technology-enhanced glove back in 2008, called Piano Touch. The glove could teach individuals how to play piano melodies in 45 minutes.

Their latest creation is an advancement on Piano Touch, which has been built around a process called passive haptic learning (PHL) – the idea that people can learn a skill unconsciously without devoting full attention to what they are learning.

“We’ve learned that people can acquire motor skills through vibrations without devoting active attention to their hands,” says Tharner.

According to the researchers, only 10% of blind people learn braille. They believe it is something that is largely neglected in schools and note that the system can also be difficult to learn as a person ages, when blindness is most common. But could this new wearable technology help with the braille learning process?

Putting the glove to the test

The team put the new glove to the test in order to see how well the technology could teach braille.

For their study, participants were required to wear the gloves during a series of tasks. The gloves consist of small vibrating motors that are stitched into the knuckles.

In the first task, the motors in the glove vibrated in a sequence that correlated with a typing pattern of a premeditated phrase in braille. The participants were given audio cues that let them know what braille letters were produced through typing that particular sequence.

Each participant was then required to type the phrase once on a keyboard without any vibrations or audio cues while the researchers measured their accuracy.

In the following task, participants were asked to play a computer game for 30 minutes – as a distraction – while wearing the glove. Half of the participants were presented with repeated vibrations and audio cues that represented the same braille phrase as the previous task, while the remaining participants acted as a control group and were only given audio cues.

The researchers note that the subjects had no previous knowledge of braille and the tasks did not include visual feedback, meaning participants were unaware of their accuracy.

Participants ‘could read and write braille’

On comparing the participants’ results with those of the first task, the team found that those in the control group had about the same level of accuracy.

However, those who had repeated vibrations and audio cues in the second task were a third more accurate, with some even gaining perfect accuracy. Furthermore, the researchers found that these participants were then able to effectively go from writing braille to reading it.

“After the typing test, passive learners were able to read and recognize more than 70% of the phrase’s letters,” says study co-author Caitlyn Seim, a student at Georgia Tech.

Seim is now in the process of conducting another study, which involves using the glove to teach the full braille alphabet to participants. She says that so far, 75% of subjects have demonstrated perfect typing accuracy. In addition, participants were able to recognize and read more than 90% of braille letters after 4 hours of learning.

Medical News Today recently reported on another creation for the visually impaired by researchers from Oxford University in the UK – “Smart glasses.” The glasses have been designed to help near-blind users navigate public spaces and better interact with others, as the glasses enhance facial features.

Written byHonor Whiteman

http://www.medicalnewstoday.com/articles/278719.php

 

 

 

The American Academy of Ophthalmology offers guidance to help improve public understanding of cataracts

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Ophthalmology

Cataract is one of the leading causes of blindness in the United States. Approximately 24.5 million Americans have the lens-clouding eye condition, and the incidence is set to grow by 50 percent by 2020.[i] As part of its efforts to support Cataract Awareness Month this June, the American Academy of Ophthalmology – the world’s largest association of eye physicians and surgeons – is sharing with the public hundreds of commonly-asked questions and answers about the condition, which affects more than half of all Americans by age 80.[ii]

If not treated through a change in eyeglass prescription or surgery, cataracts can increase risk of permanent blindness. In addition, the longer advanced cataracts are left untreated, the more difficult it can be to successfully remove the cataract and restore vision. To help people understand the condition, its causes and treatments, Academy member ophthalmologists – medical doctors specializing in the diagnosis, medical and surgical treatment of eye diseases and conditions – have responded to hundreds of queries about cataracts submitted by the public through the Ask an Eye M.D. portal onGetEyeSmart.org. The following five questions and answers about cataracts are a small sampling of what is available for public reference on the website:

Can you have 20/20 vision and still be diagnosed with cataract?

“Yes, you can,” answers Jeffrey Whitman, M.D. “Having a cataract just means that the lens of your eye has become cloudy and hardened – a process that begins at around 50 years of age and does not preclude 20/20 vision. It is only when it becomes visually significant – that is, when it degrades your vision, changes color perception, or causes glare at nighttime – that it requires surgical care.”

How can I keep cataracts from getting worse?

“Most individuals over age 50 to 60 technically have age-related changes in their lenses that might be termed ‘very early cataracts,'” says Charles P. Wilkinson, M.D. “In general, prevention is very difficult; but the most helpful practices include:

  • Avoid ultraviolet light from the sun with sunglasses
  • Avoid using steroid eye drops unless absolutely necessary
  • Avoid the rare medications that may be associated with cataract progression, including psoralens, a drug used along with light therapy to treat skin disorders; chlorpromazine, an antipsychotic; and someglaucoma medications.”

Do cataracts cause eye pain?

“Cataracts do not cause pain except if they have been allowed to remain untreated for too long,” explains Wayne Bizer, D.O. “In this case they cause a lot of pain and light sensitivity. Consult your ophthalmologist immediately if you are having eye pain.”

Why do I need to stop wearing my contact lenses before cataract surgery?

“Before cataract surgery, important measurements of the surface of your eye must be taken,” says W. Barry Lee, M.D. “Contact lenses alter the shape of the eye’s surface, which can make the measurements inaccurate and lead to poor vision after the surgery. The length of time you must not wear contact lenses prior to your cataract surgery varies depending on the type of contact lenses you wear, so listen to your ophthalmologist’s instructions carefully.”

How long is recovery time after cataract surgery?

“Typically, this should only take several days,” says Gary Hirshfield, M.D. “Of course, some issues may occur that require a longer recovery period, such as other eye conditions or rare surgery complications. Additionally, if both eyes need to be done and you are significantly near- or far-sighted, then there may be a period of time in between the surgery for each eye where the differences between the eyes may make your tasks difficult. Also, depending upon the surgical approach you may need a change in your eyeglass prescription which is usually done at about four weeks. However that can be accelerated to just several days provided you understand that the prescription may need to be revised in several weeks or months.”

“While cataracts are one of the most common eye conditions – especially for older adults – when and why to seek treatment and what kind can be a complex decision,” said Daniel J. Briceland, M.D., ophthalmologist and clinical spokesperson for the American Academy of Ophthalmology. “Some people wait too long before seeing a doctor about a suspected cataract, but they should really see an ophthalmologist for a comprehensive eye exam. Even if immediate treatment is not required, at least an ophthalmologist can confirm this and have a baseline from which to compare your vision if and when the cataract worsens later on.”

Seniors who have not had an eye exam in the last three years and for whom cost is a concern may qualify for EyeCare America, a public service program of the Foundation of the American Academy of Ophthalmology, which provides eye exams and care at no out-of-pocket cost for eligible seniors age 65 and older through its network of more than 6,000 volunteer ophthalmologists. Visit www.eyecareamerica.org to see if you or your loved ones are eligible.

See all 250 cataract-related questions and answers or submit your own question at www.geteyesmart.org/ask.

http://www.medicalnewstoday.com/releases/277794.php

 

 

 

White Boys More Likely to Be Color Blind

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April_Part 2_Ophthalmology

 

Color blindness is not colorblind, as it appears to afflict Caucasian boys at three times the rate of African-American boys, according to a new study.

Among children 37 to 72 months of age, a total of 5.6% of Caucasian boys had color blindness compared with 1.6% of African-American boys, reported Rohit Varma, MD, MPH, of the University of Illinois at Chicago, and colleagues.

Asian boys had the second highest percentage at 3.1%, followed by Hispanic boys with 2.6%, they reported online in Ophthalmology.

The overall prevalence of color blindness was about 2% — translating to 59 boys and four girls out of 4,005 children who were able to complete the test. Color blindness is generally much more common in boys than in girls, since the red and green pigment genes involved in color vision are located on the X chromosome.

“To our knowledge, no previous population-based studies have investigated the prevalence of color vision deficiency in a multi-ethnic cohort of preschool children younger than 6 years,” researchers said.

Lore Nelson, MD, a pediatrician with the The University of Kansas Hospital in Kansas City, Kan., told MedPage Today that the study confirms what she and her colleagues see in clinical practice.

“The study is a reminder to screen more closely those groups with a higher incidence of color blindness,” she said.

The recommended age to begin vision screening — 3 years — is endorsed by the American Academy of Pediatrics, the American Academy of Ophthalmology, and the American Association for Pediatric Ophthalmology and Strabismus.

For their analysis, Varma and colleagues recruited the children from Los Angeles and Riverside counties in California as part of the population-based Multi-Ethnic Pediatric Eye Disease Study (MEPEDS).

When researchers compared older (61 to 72 months) with younger (37 to 60 months) children, they found no difference in prevalence of color blindness, nor did they find a difference between younger and older kids within any ethnic group.

They noted that testability was high by the age of 4 and increased linearly with age:

  • Ages 30 to 36 months: 17% were testable
  • Ages 37 to 48 months: 57%
  • Ages 49 to 60 months: 89%
  • Ages 61 to 72 months: 98%

The divide along ethnic lines is also reflective of findings in older children, Varma and colleagues pointed out. Data from the CDC’s National Health Examination Survey from the early 1960s found a 3.8% overall prevalence of color blindness in children ages 6 to 11 years(about 900,000 children affected). Among boys, race appeared to be significantly related to the presence of color blindness: 7.4% for whites versus 4% for blacks.

The corresponding study in children 12 to 17 years conducted in the latter half of the 1960s found an overall prevalence of 4.3% (again about 900,000 children affected), but the difference between white and black boys was not significant (7.7% versus 6.4%).

An earlier collaboration between MEPEDS and the the Baltimore Pediatric Eye Disease Study (BPEDS) also found ethnic differences regarding myopia and hyperopia.

Varma and colleagues noted that their study has some strengths, including “the large MEPEDS population-based cohort and the fact that standardized color vision testing was administered to the children by eye care professionals.”

Image courtesy of https://www.facebook.com/ResearchtoPreventBlindness

http://www.medpagetoday.com/Pediatrics/GeneralPediatrics/45100